Portable sheet metal bending tool



PORTABLE SHEET METAL BENDING TOOL Filed June 25, 1938 2 Sheets Sheet 1 fnz/ezzzfor Agrewziffiexdali jyrizgs.

d 4, 1941 A. M. HEXDALL. 2,233,937

PORTABLE SHEET METAL BENDING TOOL Filed June 25, 1938 2 Sheets-Sheet 2 Patented Mar. 4, 1941 UNITED STATES PATENT O F'HCE Andrew M. Hexdall, Morris,,lll.

Application June 25, 1938, Seri'alNo. 215,941

'7 Claims.

The invention relates to sheet metal bending tools and more particularly to portable tools of this type which may, for example, be used to bend the marginal edge portions of metal sheets.

The general object of the present invention is to provide a tool of the type described which is thoroughly portable and embodies a self-contained power unit such that it maybe readily carried to the work site and used without diniculty to operate upon sheet metal structures which may even be installed in a building and inaccessible to ordinary stationary sheet metal bending brakes or tools.

Another object of the invention is to provide a tool of the type described so constructed; that it may be readily applied by the operator to variious parts of assembled orsemi-assembled sheet metal structures without the necessity of moving the latter.

Still another object of the invention is to provide a tool of the type described for quickly and efiectively finishing Pittsburgh or similar joints at the juncture of two angularly disposed metal sheets in which finishing operation a marginal portion of a metal sheet must be bent through a substantial angle, usually 90, and pressed flat against the surface of one of the sheets.

Further objects and advantages of the invention will become apparent as the following description proceeds taken in connection with the accompanying drawings in which:

Figure 1 is a side elevation of a tool. embodying the present invention and shown as operating upon a sheet metal structure provided with a Pittsburgh joint;

Fig. 2 is an enlarged vertical sectional view of the tool and sheet metal structure shown in Fig. 1;

Fig. 3 is an enlarged partial bottom plan view of the tool shown in Fig. 1;

Fig. 4 is an enlarged front end elevation of the tool of Fig. 1 with the sheet metal structure operated upon shown in dot-dash lines;

Fig. 5 is a detail perspective view of the metalbending plunger included in the tool.

The invention has been shown herein as em-. bodied in a tool especially designed for finishing so-called Pittsburgh joints in sheet metal structures although it may, of course, be used, or modified for use, in'performing a number of other types of sheet metal bending operations. The tool has been shown herein as being utilized in the finishing of a Pittsburgh joint between two sheets of metal l0 and l I (Fig. 2) which may, for example, be part of an air conditioning conduit; system. In fashioning the joint between the sheets of metal a reentrant bend is formed in the marginal portion of. the sheet H as indicated at l2 and a laterally extending flange l3 on the sheet Hlis inserted into the recess formed in the folded edge portionv of the sheet II. In finishing the. joint, it is necessary to bend the edge or" flange, M on the sheet II from its.up right position, shown in dot-dash lines in Fig. 2, through an angle of substantially 90 and to 10 pressitsmoothly against the, surface of the sheet H3; in' the, position shown in full lines in Fig. 2. It-is this: finishing operation which thetool hereindisclosed is particularly designed to accomplish. The, portability'of the toolv is a highly important feature, when the sheet metal structure is being erected in, or" as a part of, a building so that at leastthe finishing operations must be carried out inlocations which are comparatively difiicult of access. Even: when the sheet metal structure is erected in a shop, the bulk of the structure oftenrenders it, difficult, if not impossible; to utilize conventional stationary sheet metal working tools:

Inthe form of the invention illustrated the toolincludes an elongated body member or casting 1 5' sloping-upwardly to terminate in a rounded rear or butt end to which is bolted an electric driving motor I6. The driving motor includes a suitable cup shaped enclosing casing fast on the body casting l5. The lines of the casting l5 are faired into the round walls of the motor casing 50 as to lend the device a pleasing appearance. Current maybe supplied to the motor through a suitable flexible cable (not shown).

The forward end or nose l5 of the body casting- 15 is notched out as indicated at l5 (Fig. 1) in order to form a recess dimensioned to embrace the corner juncture between the two angularly disposed metal sheets I 0- and H. Within this 40 notch is mounted a power driven reciprocating metal bending tool shown as a plunger ll axially reciprocable in a bore I8 fashioned in the body casting 15' (Fig; 2). A suitable bearing sleeve or liner I9 slidably supports the plunger within this bore.

A head" 20' (Figs. 2 and 5). is fashioned on the forward end of the plunger I1 for bending and smoothing the sheet metal flange M which it contacts. This head is of generally semi-conical shape with a smoothly rounded nose or end. It will be noted that the plunger I1. is disposed for reciprocation along the upper wall of the notch 15 in the: nose: of the body casting l5 and the head 2.0 tapers away toward this wall of the l notch. By utilizing a reciprocating plunger head of this shape the flange 14 can be bent and smoothed nicely into position as the tool is moved progressively along the corner juncture between the sheets l and l I.

A suitable driving connection is provided Within the body member I for reciprocating the plunger I1 by the rotatable electric motor Hi. This drive connection has been shown as including a speed reduction gearing mounted within a recess 2| (Fig. 2) cored out of the rear end of the casting '15. The speed reduction gearing comprises a pinion 22 on shaft 23 of the motor 16 and meshing with a gear 24 carried by stub shaft 25 journaled in suitable sleeve bearings 26 and 21 in the casting l5 and motor housing. A swash plate 28 fast on the stub shaft 25 meshes with a suitably contoured complemental notch 29 in the plunger [1.

In order to locate the metal-working plunger 11 properly with respect to the sheet metal on which it operates guiding abutments have been provided on the tool. This guiding arrangement preferably includes abutments located generally forwardly of the plunger for engagement with the sheet I 0 and also an abutment laterally ofiset from the plunger and engageable with the sheet H. In the present instance the abutments engaging the sheet Ill are shown in the form of balls 30 journaled in suitable recesses in the lower ends of inverted retaining cups 3|, carried by screws 32 threaded in vertical brackets 33 on the nose portion of the body casting 15 (Figs. 2 and 4). It will be noted that the balls 30 are located on opposite sides of the plunger head and generally forward of its path of travel. The screws 32 may be threaded in and out in order to change the vertical adjustment of the balls 30 with respect to the lower side of the plunger I1 thereby accommodating the tool to sheet metal of different thicknesses. The screws 32 are retained in their adjusted positions by lugs 34 yieldably urged into engagement with the peripherally notched heads 35, on the screws 32,

l by cantilever supporting springs 36 (Fig. 2).

The third guiding abutment which engages the sheet H is formed by a ball 31 journaled in a recess 38 fashioned in the front end of an extension 39 on the bottom of the body casting I 5. The ball 31 projects through an aperture of smaller diameter in a retaining plate 40 screwed to the front of a projection 39. With the arrangement described, the tool is given a three point rolling contact with the workpiece and can be readily adjusted for use with metal of different gauges.

As a means of supporting the tool while in operation two manual handles are preferably provided. In the construction illustrated these include an inverted pistol-grip handle 4| (Fig. 1) on the forward end of the body member 15 and a U-shaped handle 42 fast on the casing of the motor 16. A suitable control switch 43 for the motor l6 may be included in the handle 42. The handles 4| and 42 are preferably both located substantially on the longitudinal center line of the tool (Fig. 4,). With this arrangement either a left or right handed operator can operate the tool with equal ease and use it to work on sheet metal joints located in almost any position. The handles described also serve as a convenient means'for carrying the tool about as well as supporting it while in operation.

In the operation of the tool described, the abutment adjusting screws 32 are threaded in or out until the lower surface of the guide balls 30 are located a distance beyond the lower edge of the plunger head 20 substantially equal to the thickness of the flange l4. The tool is then pressed against the work (in the position shown in Fig. 1) so that the notch 15' in the nose of the tool embraces the corner of the sheet metal structure which is tobe operated upon. The operator then starts the motor 16 so that the plunger I1 is reciprocated at a relatively rapid rate, and moves the tool progressively along the joint between the sheets 10 and II as, for example, to the left as viewed in Fig. 4. At each reciprocation of the plunger 11, the portion of the flange 14 in front of it is bent through an angle of substantially 90 and pressed flat against the upper surface of the sheet 10. The guide ball 31, below the plunger,

is located in such a manner that the reciprocating plunger will occupy substantially the position shown in Fig. 2 at the forward end of its working stroke. It will be noted that in this position the tapered forward portion of the head 20 has passed completely over the flange I 4 so that the flange is contacted throughout its length by the cylindrical bottom surface of the plunger and plunger head. By this type of operation the finishing of a joint such as that illustrated can be very quickly and efficiently completed.

Although a particular embodiment of the invention has been shown and described in some detail for illustration of its various novel features, there is no intention to limit the invention to such embodiment but, on the other hand, the appended claims are intended to cover all modifications --and alternative within the spirit and scopeof the invention.

I claim as my invention:

1. A power actuated portable sheet metal bending tool comprising, in combination, an elongated body member having means thereon for manually supporting the same, the forward end of said body member being notched out to form a recess dimensioned to embrace a corner juncture between two angularly disposed sheets of metal, the walls of said recess being disposed substantially at right angles to each other, a plunger having a metal-bending head thereon, means supporting said plunger for reciprocation along one of said recess walls, a guiding abutment on said body member located generally forwardly of said head and adjustable transversely to the path of reciprocation thereof, a second abutment located adjacent the other of said walls of said recess and displaced laterally from the path of reciprocation of said plunger,

said second abutment facing generally axially of said plunger toward the headed end thereof, and power actuated means on said body'member for reciprocating said plunger.

2. A power actuated tool for bending sheet metal comprising, in combination, a plunger having a metal-bending head thereon, means supporting said plunger for reciprocation, a guiding abutment on said supporting means located generally forwardly of said head and adjustable transversely to the path of reciprocation thereof, a second guiding abutment on said supporting means laterally displaced from the path of reciprocation from said plunger and facing generally axially thereof toward the headed end thereof, and power actuated means for reciprocating said plunger.

3. A power actuated tool for bending sheet metal comprising, in combination, a plunger having a metal-bending head thereon, means constructions supporting said plunger for reciprocation, two guiding abutments on said supporting means located generally forwardly of said head and on opposite sides thereof, means for adjusting said abutments transversely to the path of reciprocation of said head, a third guiding abutment on said supporting means laterally displaced from the path of reciprocation of said plunger and facing generally axially thereof toward the headed end thereof, and power actuated means for reciprocating said plunger.

4. A power actuated portable sheet metal bending tool comprising, in combination, an elongated body member, a plunger mounted for reciprocation on the lower side of said body member, said plunger having a metal-bending head on the forward end thereof, twoguiding abutments on said body member located on opposite sides of said head and adjustable transversely to the path of reciprocation thereof, a third guiding abutment on said body member located below said plunger and facing generally axially thereof toward the headed end thereof, and power actuated means for reciprocating said plunger.

5. A power actuated tool for bending sheet metal comprising, in combination, a plunger having a metal-bending head thereon, said head presenting an active face tapering away from the forward end thereof, means supporting said plunger for longitudinal reciprocation, a guiding abutment on said supporting means adjustable transversely to the path of reciprocation of said head, a second guiding abutment on said supporting means displaced laterally from the path of reciprocation of said plunger on the side thereof on which said tapered head face is located and facing generally axially of said plunger toward the headed end thereof, and power actuated means on said supporting means for reciprocating said plunger.

6. A power actuated portable sheet metal bending tool comprising, in combination, a body member having a recess therein, a metal-bending head, means supporting said head on said body member for movement in a fixed path in said recess, a self-contained power actuating device for said head on said body member, a plurality of guiding abutments on said body member disposed at spaced points with relation to said bending head path, and means for adjus ably projecting at least two of said abutments into said recess a predetermined distance to determine adjustably the positional relation of said fixed path for the bending head to a work piece inserted in said recess and engaged by said abutments.

'7. A power actuated portable sheet metal bending tool comprising, in combination, an elongated body member having manual supporting means thereon and a recess defined by two Walls disposed substantially at right angles, a metal-bending head, means supporting said head on said body member for movement in a fixed path in said recess lying generally parallel to one of said recess walls, a self-contained power actuating device for said head on said body member, a plurality of guiding abutments located on said body member projecting into the recess beyond the planes of respective ones of said walls, and means for adjustably shifting at least one of said abutments a predetermined distance beyond the face of the adjacent one of said recess walls to determine adjustably the positional relation of said fixed path for the bending head to a work piece inserted in said recess and engaged by said abutments.

ANDREW M. HEXDALL. 

